1. Field of the Invention
The present invention relates generally to mobile communications, and more particularly to systems and methods to locate objects by using mobile devices powering radio frequency devices.
2. Description of the Related Art
Many systems exist to identify and localize objects. In particular, several solutions have been developed to localize stolen or lost objects.
The existing solutions present several drawbacks. An efficient localization system would require solving several cumulative problems (energy, sensors, communication, and location): finding first the required energy for powering a tracking device apposed on an object, having a sufficient number of detectors of the tracking device, having efficient communication means, solving the determination of the location of the detected tracked device.
Relating to the “energy” problem, many solutions require a source of energy such as a battery (in Argos' buoys or PIEPS/ARVAs avalanche transceivers for example); it is also not convenient for small objects. Some others, which do not require a source of energy, do not enable a remote detection (engraved identifiers on cars) and do not enable a localization of goods.
Relating to the “sensors” problem, difficulties arise, as to how to implement a sufficient number of captors or sensors. Military forces sometimes send a huge number of sensors on battlefields to be able to detect targets. The objects to be located can be fixed in space or can be in movement. In this last case, the use of fixed detection devices can be imagined: when the object to be detected passes nearby a detection device whose location is known then the localization problem is solved, but this solution presents many drawbacks (costs, tracking, etc).
Regarding the “communication” problem, it is required to setup a complete communication infrastructure. Questions arise as to costs, technology and integration with the sensors for example. At last, when choices have been made about the previous aspects, a question arises as to the determination of the location.
In order to solve the primary energy problem, the prior art sometimes show the use of (passive) RFID tags. The existing solutions almost always require the use of RFID readers.
For example, patent document U.S. Pat. No. 6,978,118, entitled “Apparatus, system, method and computer program product for implementing an automatic identification system with a personal communication device to improve functionality of a personal communication device,” discloses a data carrier that contains one or more data items and which transmits a data signal wirelessly to a personal communication device equipped with an RFID reader. The personal communication device decodes the data signal and at least a portion of the data is used by the personal communication device to establish a communication connection with another device or network. The data subsequently transmitted by the personal communication device is accomplished using GSM, GPRS, WAP, EDGE, UMTS or other similar wireless network protocol. The communication connection is used to provide a request for a service such as a phone call, an Internet connection, a third party service, or to request for the storage of data in a network.
This document thus discloses a system and method using a communication device equipped with an RFID reader. This solution is not convenient since the RFID reader would consume a lot of the (limited) energy available in the mobile communication device: in order to detect passive tags (the mobile phone being in standby or in communication mode), the reader must be active (in operative mode) all the time. The document does not address the other issues (energy, sensors, communication, and location).
Patent document US20070229270, entitled “RFID System with RF bus,” discloses a radio frequency identification (RFID) system which includes an RFID reader, an RFID tag, and a network connection module. In the detailed description, and FIG. 2 is a schematic block diagram of an embodiment of an RFID (radio frequency identification) system 50 that includes a communication device, a computer, and/or a server 52, a plurality of RFID readers 54-58 and a plurality of RFID tags 60-70. The document discloses a system where the RFID readers 54-58 collect data as may be requested from the communication device.
This document thus discloses a system where RFID readers interact with communication devices. The problem posed by energy still remains. The solution is depending upon RFID readers are in active mode or not and the use of several devices is required.
Patent document US20070066278, entitled “Mobile communication terminal including RFID reader and transception method thereof,” discloses a mobile communication terminal including a Radio Frequency Identification (RFID) reader, and more specifically having a shared antenna for RFID transception and wireless telecommunications transception.
This document once again does not solve the energy problem; it still requires embedding an RFID reader on the mobile communication device.
The patent document US20080018467, entitled “RFID Power from handset transmissions,” discloses a radio frequency identification (RFID) tag which includes a transceiver and a component coupled to the transceiver. The transceiver is adapted to wirelessly receive power from an RFID reader and/or from a mobile communication device. The power received from the mobile communication device is used to power the component, providing an alternative power source (cellular beacons) that uses no additional handset power.
This document thus discloses an RFID tag which includes two components, one of which (e.g., a sensor) can be powered by the mobile communication device itself. More precisely, the document discloses a radio frequency identification (RFID) tag which includes a transceiver and a component coupled to the transceiver. The transceiver is adapted to wirelessly receive power (from an RFID reader and) from a mobile communication device. The power received from the mobile communication device is used to power the component. According to the description, the mobile communication device 40 preferably is not an RFID reader or RFID-compliant at all. In the detailed description, at paragraph [0014], the document discloses that “[t]he tag's receiver may be designed to operate in several modes . . . . (2) Operation as a cellular-mode receiver, in which energy is gathered from one or more of the standard cellular uplink frequencies. Beacons from the cellular handset may be used to prompt the RFID device to transmit its information . . . ” This document thus proposes an interesting solution to the energy problem but it does not address the localization issue at all (as well as the communication and location problem).
Accordingly, there is a need for a method or system that enables the location of an object, where such method or system solves or overcomes the energy, sensors, communication, and localization issues.